The present invention relates to a protection system, a virtual concatenation processing block, a node and the ring network, in which virtual concatenation process and link capacity adjustment scheme (LCAS) process are carried out on the ring network to exploit bands or channels effectively, and more particularly to a protection system, a virtual concatenation processing block, a node and a ring network, in which traffic sent to a protection channel by virtual concatenation process and LCAS process when no failure occurs on the network can be transmitted even when failure occurs on the network.